Garrett Sea Hunter Mark II Review

Garrett Sea Hunter Mark II Metal Detector Review

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Dive headfirst into sunken treasures of the deep with the Garrett Sea Hunter Mark II metal detector. 

This machine incorporates Pulse Induction technology that goes deeper than conventional VLF machines. 

If you’re after gold buried under wet sand or at the bottom of the seabed, it’s a job for the Sea Hunter. 

Although PI technology can cost significantly more than VLF tech, the Sea Hunter comes at a price point that beats out some of the best VLF machines on the market

Which should you choose?  Let’s help you answer that question. 

At a Glance…

✔️ Best Feature: Pulse Induction Technology

Worst Feature: 1-year Warranty

👌 Ideal For: Beach, Shallow Water, Submersion, Scuba Diving, Gold, Coins, Relics, Jewelry, Intermediates, Experts

  • Pulse Induction Technology
  • Discrete Trash Elimination Mode
  • Submersible
  • 22 Frequencies
  • Versatile Assembly

Our Verdict: The Garrett Sea Hunter Mark II is an excellent underwater metal detector for those willing to brave brackish water conditions.  As a PI machine, it’s right within the entry-level range, but it has some extra perks that make all the difference in the hunt. 

Who is the Garrett Sea Hunter Mark II Best Suited to?

The Sea Hunter Mark II is definitely geared towards intermediates and experts that take treasure hunting to the next level – under water.  Since it has no display to help interpret data gathered, you’ll have to depend on audio tones to decipher your finds.  This may be difficult for beginners to start out with.  However, if you’re in the market for an underwater metal detector for beginners, the Sea Hunter may be your best friend due to price point and features. 

How Does the Garrett Sea Hunter Mark II Perform?

The Sea Hunter uses PI (Pulse Induction) technology that is primarily used for ignoring conductive and non-conductive mineralization in the environment to detect only metals.  It has high sensitivity, and this model has 22 frequencies to enable the best detection in the harshest areas.  The Garrett Sea Hunter is an excellent pulse induction metal detector.

The lack of a visual indication display to incorporate in data interpretation is a moot point due to the conditions of brackish waters that reduce visibility.  You will have to rely upon audio tones and memory of the features on the control box.  Fortunately, the interface is rather simple to use with its two potentiometers, power switch, and headphone jack. 

Features & Benefits

Pulse Induction Technology

PI technology is considered one of the best types of metal detector technology due to its deep soil penetration and its ability to pick up even the smallest targets buried within highly mineralized environments.  However, due to its high sensitivity, metal differentiation may be difficult to achieve, and it can be prone to various types of signal interference. 

The benefits far outweigh the disadvantages, and in this case, if you’re searching for gold or other objects in high-salt areas, and underwater, the Sea Hunter will perform, and you’ll be sure to reap results. 

Discrete Trash Elimination Mode

PI metal detectors struggle to reliably discriminate between various metals.  However, the disadvantage of using discrimination modes is that it decreases depth and sensitivity, so you’re likely to pass over a good target while filtering out the unwanted.  But, this model does incorporate some form of discrimination which are the Sea Hunter’s primary search modes: Standard Trash Elimination and Discrete Trash Elimination.

Standard mode is a conventional search mode found on a PI detector.  While you can dial in for enough elimination of poor conductive objects, small coins, relics, and jewelry will still produce a strong enough signal to be detected.  It’s also good for pinpointing a good target’s location, so you know where to dig.  The Discrete Trash Elimination mode is highly effective for areas with excessive trash. 

It discriminates more precisely against unwanted targets like pull tabs without significantly affecting detection response against good targets like thin gold rings.  As a dynamic mode, it must be in motion to provide a response. 


As a fully waterproof unit, the Sea Hunter can be completely submerged underwater making it an excellent option for scuba diving and finding sunken treasure.  It’s completely protected for up to 200 feet (65 m).  The control box is double O-ring sealed, including the battery compartment.  The headphone jack is also waterproof, and the included headphones are submersible, too. 

22 Frequencies

The Sea Hunter has multiple, adjustable frequencies operating at 7.5 kHz which is equal to 750 pulses per second.  The 22 frequencies are manually adjustable allowing the user to fine-tune the metal detector to provide the best depth and sensitivity trade-offs for your hunting area and goal targets. 

Versatile Assembly

The Sea Hunter Mark II has an adjustable length from 28” to 52”.  You can assemble the metal detector in four configurations: full length, long, short, or hip mount.  Its versatile assembly means you can find the right weight to comfort ratio for searching underwater or detecting along the shoreline for hours of treasure-finding. 


1-year Warranty

The Sea Hunter Mark II is only covered with a 1-year limited warranty by the manufacturer.  This is unfortunate as most other metal detectors covered by the brand are warrantied for at least two years.  Keeping your metal detector clean and performing maintenance will help to protect your investment.  It’s also a good idea to purchase a searchcoil cover, rinse down the detector after use, and remove the battery compartment when storing it away for long periods of time. 

No Iron Elimination Mode

While PIs are great for depth, they’re notorious for picking up all sorts of metals such as iron.  As there is no specific iron elimination mode, you may have to increase elimination settings to dial it out.  However, this could prevent you from detecting good targets.  It also presents an issue for black sand environments.  It could be nearly impossible to completely dial out for iron, and so a strong magnet attached to your digging tool can be of great help here. 

Popular Questions

Can You Use an Underwater Metal Detector on Land?

The Garrett Sea Hunter Mark II can be used on land on and underwater in both fresh and saltwater conditions.  However, it’s an excellent machine for underwater conditions when you want to go far beyond the shoreline and under the breaking wave of the surf.  On land, you can use the Sea Hunter to detect all metals with some, but limited, levels of discrimination.  Typically, a serial underwater hobbyist will have a separate land detector with many features that an underwater metal detector will not have. 

How Can You Use the Sea Hunter Mark II Without Headphones?

Most underwater metal detectors cannot be used without headphones.  They do not have external speakers to provide submersible benefits.  Additionally, the audio volume can be controlled via the Threshold setting on the control box.  Set it to low to and adjust for your hearing needs and background noise.  Note, the background audio threshold is continuous, but you will be able to detect variations in the signal within the acceptable range of the knob’s setting. 

What Type of Batteries Does the Garrett Sea Hunter Use?

The Sea Hunter requires 8x AA batteries.  This will provide you with 18-22 hours of operation.  While there is no display to indicate battery level, there is a battery test you can perform.  When you power on the detector, you’ll hear a series of beeps.  Four beeps indicate full battery power.  One beep indicates the batteries should be replaced as it will affect performance. 


The Garrett Sea Hunter Mark II has more than enough to get you hunting below the water’s surface. 

This is extremely convenient for hobbyists who want to search beyond the ‘towel line.’  As a PI metal detector, you’ll have the benefit of ignoring salt minerals while improving detection depth. 

The Sea Hunter also comes with two searchcoils: 8” and 10” x 14” mono loop coils.  Submersible headphones, a belt pouch, and an instructional DVD are also included in the buy. 

While experts will find it suitable for their needs, beginners will enjoy the chance to explore underwater world and its hidden treasures.

Further Reading:

Back to Best Pulse Induction Metal Detectors

Back to Best Underwater Metal Detectors